Paul,
I agree with your assessment of the parasite situation in reef tanks. I don't bother "battling" it, either. If I introduce a new fish or I do something else that stresses my fish, I can safely presume that they will get a small outbreak of Ich. It has never been a big deal. It goes away on its own; but if it gets worse than I expect, the most I will do is add some selcon and garlic to their food, for a little boost.
I have been in the hobby for a whooping 1 year. In that year I have learned that you can accept Darwinism, or you can spend money to postpone it; but Darwin will win. I think this hobby's industry is the biggest problem in that regard. All the videos and googles say, in order to keep a healthy reef tank you NEED this and you NEED that; but who is posting those videos and googles? (Hint: the people selling stuff: BRS, Saltwater Smarts, Two Little Fishies, etc) Not to mention, all those "needs" are simply overpriced things that are often developed for other hobbies and/or industry(s), repackaged and renamed, and then sold for 5 times what they normally cost (i.e. $20 PH/kH buffer aka: $2 baking soda). The kicker to the price thing is: there are people on other forums that defend those prices and reject any semblance of common sense; because by buying those over priced things, you are helping the hobby, which is false.
Then you have the type of people who think that they are all knowing and are happy to bestow some of their knowledge and/or opinion (those words are interchangeable in this hobby). A good example of that type of person is seen in the "Tang Police." The ones that know how the fish feel and how it/they will die if you keep them in a tank smaller than the ocean.
As someone new to all of this (prices, other hobbyists, equipment, etc.), it is very intimidating.
When It comes to getting out of the hobby, I think it really just comes down to time, motivation, funds and the season. During the summer, many of us don't spend as much time looking at our tanks or working on them. So, if something happens with the tank, some aren't as enthusiastic about getting it back up. During the winter, it is the opposite.